Device for cutting cavities

ABSTRACT

A device for cutting cavities, or the like, in heat severable material providing for undercut surfaces in the cavities said device comprising means to move the material with respect to heated, formed wires so that the desired cavity shape is cut.

United States Patent Ross 'Jan. 21, 1975 [54] DEVICE FOR CUTTING CAVITIES Primar Examiner-J. M. Meister 76 In m c L. R 309 Jackso Rd., Y 1 ve or fi i 82 5 06082 n Attorney, Agent, or Firm-Frederick W. Turnbull [22] Filed: Nov. 23, 1973 [21] Appl. N0.: 418,764 [57] ABSTRACT U-S. A device for utting cavities o [he kg in heat ever- 83/409 able material providing for undercut surfaces in the [51] Int. Cl. B29C 7/10, B26f 3/12 cavities said device comprising means to move the ma- Field Of Search 307-1, 171 terial with respect to heated, formed wires so that the desired cavity shape is cut. [56] References Cited UNITED STATES PATENTS 5 Claims, 16 Drawing Figures 3,731,567 5/1973 Ross 83/1 PATENTEDJANZ Hers saw 1 UF 4 PATENTED JAN 21 I975 SHEET 2 [IF A FIGA DEVICE FOR CUTTING CAVITIES This invention is an improvement on the device of applicants U.S. Pat. No. 3,731,567 issued May 8, 1973.

The machine of the Patent drops a block of material onto a heated wire tool then pushes the block to move the tool the desired length of the cavity being out then, by moving the tool downwardly as the block continues to be moved, the tool is withdrawn from the material.

While it is possible to provide an undercut section lengthwise of a cavity by the earlier machine it is impossible to form undercuts at the ends of the cavity.

It is, therefore, an object of the present application to provide a device or machine by which many shapes of cavity not possible with the earlier machine may be produced.

Other and further objects and advantages will appear from the following specification taken with the accompanying drawings in which like reference characters refer to similar parts in the several views and in which:

FIG. I is a broken away perspective view showing the principal moving parts;

FIG. 2 is a fragmentary view showing one of the product carriages and product clamps;

FIG. 3 is a fragmentary plan view showing one product carriage and product clamp;

FIG. 4 is a fragmentary longitudinal section through the product hopper to supply the material to be cut and showing the shelf to which each block of material is successively delivered.

FIGS. 5, 6, 7, 8, 9 and show the basic operation of the machine cutting a cavity without undercuts at the ends;

FIGS. ll, l2, l3 and 14 show the use of curved cam faces to modify the relative speed between the material being cut and the cutting wires.

FIG. shows cams shaped differently than those used in FIGS. 11 to 14; and

FIG. 16 shows in section a block cut by the machine using the cams of FIG. 15.

Considering FIG. 1 it will be seen that at each side of the machine there is a horizontal rotatable drive shaft 1 and l, and sloping die carrier rails 2 and 2'. The die carrier rails 2,2 being shown as two parallel rods, but any equivalent rail would do.

Above rotating shafts l, l are product carrier stabilization shafts 3, 3 which merely guide the product carrier to be described below, which carriers are moved to and fro along the shafts l, 1'.

Mounted on the die carrier rails 2, 2 are die carriers 4, 4 which may be counter weighted so that while they will slide along rails 2, 2' they will not move along the rails 2, 2' except under the pressure of cams (straight or curved) mounted on the product carriers which are moved along drive shaft 1, l.

The die carriers 4, 4' include cam engaging rollers 5, 5' against which cams to be described below, will push to move the die carriages up the sloping rails 2, 2', and the die carriers also are provided with die mounting clips 6, 6' to which a selected die will be bolted. The dies may be similar to the dies used in U.S. Pat. No. 3,731,567.

It will be noted that the drive shaft 1 and die carriage rails 2' at the left hand and of the machine as seen in FIG. 1 are mounted on a movable bulkhead 7. The bulkhead 7 is supported by two elements 8 and 9 which may be heavy rods as shown, or any other support for slidably supporting the bulkhead 7.

Three threaded shafts 10, 11, and 12 driven by a common chain 13 run in nuts secured on bulkhead 7 to adjust its position.

Mounted on drive shaft 1 and 1' are mirror image identical product clamps as seen in FIGS. 2 and 3. Conveniently, the product clamps are supported on the rotatable drive shaft 1, 1' by linear actuators 14, 14' which may be of the type made by Textrol Systems, Inc. of Carlstadt, New Jersey. The linear actuators must move the product clamps along the shafts l, l at the same speed and in the same direction. If such linear actuators are not used, the shafts l, 1 may be merely tracks or guides and any conventional means may be used to move the product clamps simultaneously.

Straight cam and stabilizing elements 15, 15' are seen in FIGS. 1 to 10 mounted adjacent the linear actuators 14, 14' to move therewith and, being pierced by both shafts l, 1' and 3, 3' the straight cams l5, 15' are held in vertical position to project downwardly to engage the die carriage roller 5 to urge the die up the die carrier rails 2, 2' or to engage a roller on a die, as described later, to urge the die down the die carrier rails 2, 2'. Other than straight cams are shown in FIGS. 11-15.

Clamps to hold successive blocks of material to be out are mounted on the linear actuators which clamps preferably each comprise a fixed clamp jaw 16, mounted for movement with the linear actuator, and a movable clamp jaw 17 which, being mounted on rods 18, or a similar guide that is movable with respect to the fixed clamp jaw 16. It will be understood that by moving movable jaw 17 along rods 18, the clamp may be adjusted to accommodate different sizes of blocks of material.

The clamp is released when the product carrier arrives at the front of the machine by a lever 19 (See FIG. 2), pivoted to the product carrier, when it strikes the front frame or a projection thereon, the other end of lever 19 engaging a block 8a to push rods 18, and therefore jaw 17 forward. The product then falls free at the front of the machine.

Upon the product carrier arriving at its delivery point, front linear actuator control solenoids S in FIGS. 2 and 3 are operated that reverse the direction of the linear actuators. Just before, or just as, the linear actuators are reversed, a lever 20 is pushed by the product carrier so as to tension spring 21 which is secured to a shelf 22 which swings shelf 22 into the position seen in FIG. 3. A second spring 23, will pull shelf element 22 out of the way as the product clamps move rearwardly. The time of action of product clamp release is adjusted to be prior to the shelf movement, so by the time the shelf is in place to receive the next block of material to be cut, the last cut piece has fallen into a receptacle, not part of the machine.

When the product carriers have moved the shelf elements 22, 22' into position a solenoid 24, seen in FIG. 4 is actuated to permit the stack of blocks of material 25, 25', 25", etc. to descend so that the lower most block 25 rests on shelf elements 22, 22'. Since at this time the movable clamp jaws 17, 17' are in released position, the block 25 descends to rest on shelves 22, 22 between jaws 16, 16' and 17, 17.

The product carriers are then actuated by solenoids 5, 5 to start the product carriers rearwardly of the machine to commence operation on the block 25. As the product carrier moves rearwardly springs 27, 27' pull rods 18, 18' rearwardly so clamp jaws 17, 17' contact block 25, and pull it against jaws 16, 16 to securely hold the block in position during the cutting of the cavity in block 25.

A die is placed in the machine securely bolted to clips 6 and 6'. This die may be of any selected design according to the shape and depth of the cavity to be cut. Appropriate simple dies are illustrated diagramatically in FIGS. 5 to 10, and in FIGS. 11-14. Such dies may be similar to dies shown in applicants Patent or in copending application Ser. No. 355,170 filed Apr. 27, 1973. The die shown in FIGS. 5 to inclusive may consist of two wires A and B extending horizontally from the side plate elements of the die, which are flat plates having apertured flanged to be bolted to clips 6 and 6' then extend upwardly in an inverted U shape.

Considering FIGS. 5 to 10 inclusive the simplest cam and a simple die is used to illustrate the mode of operation of the device. The cams 28, 28', starting rearwardly (to the left) in FIG. 5 are out of contact with die frames 29 that carries wires A and B. As noted above, as the product carrier starts to move to the rear (to the left in FIG. 5) the product block 25 is gripped between jaws 16 and 17. As the product carrier continues to move rearwardly, the lower ends of cam 28 passes over a roller 30 on the die side plate. The die on the other side has a roller 30 to cooperate with the cam 28' of the machine. When Cam 28 strikes the roller 5 as seen in FIG. 6 the die carrier 4 is moved upwardly along rail 2 at the same horizontal speed as the product carrier with block 25. This movement raises the die so that the wires, FIGS. 6 and 7 cut vertically into the block 25. FIG. 7 shows the full penetration of the wires into the block 25.

The product carriers having reached their destination toward the left, a solenoid S seen in FIG. 2, reverses the direction of movement of the product carrier so the block 25 is moved to the right as seen in FIG. 8 so that the wires A and B cut horizontally at full depth until the cam 28 contacts roller 30. The die carriage, under the pressure of cam 28 on the roller 30 then moves horizontally at the same speed as the block 25 held in the product carrier, but moves downwardly along rails 2 until the cam 28 passes over roller 30, as seen in FIG. 9, at which time the waste material falls out of the cavity.

The product carriage continues to move forwardly, to the right in FIG. 10 until lever 19 releases the block 25, which falls out of the machine; then lever 20 pulls shelf element 22 into position as seen in FIG. 5, block 25 will be released to position on shelf element 22, will be gripped by jaws 16 and 17 and will be processed as block 25 was.

The straight cams shown in FIGS. 5-10 do not make shaped cuts at the ends of the cavity. From FIGS. l1, 12, 13 and 14, however, we see a shaped cam in use. As roller 5 moves upwardly under the movement of cam 28a the die 29a is moved at a variable horizontal speed so that the cut made by wires A'B are not straight vertical cuts but, rather, follow the shape of cam 28a as seen in FIGS. 11 and 12. FIG. 13 shows the completion of the horizontal cut, then the cam surface 28b comes into use and the shape of the second cut end of the cavity, as seen in FIG. 14 is determined by the shape of cam 28b In FIG. 15 a cam surface 280 is shown which, used with a cam 28a, will give a cavity as shown in FIG. 16 with a single wire.

It is at once clear from the above, that many cam shapes may be used to cut many different shapes of cavity in the blocks and, by varying the location of roller 30 and the vertical length of the cam 28 or other cam shapes, and by using wires shaped as suggested in applicants above referenced application and patent, cavities having undercut sides and ends may be made in any size block of material.

The hopper construction is adapted to receive any sized blocks as laterally the hopper elements 31, 32 at the right hand end in FIG. 1 are fixed but the hopper elements 31 32 at the left handed are mounted on bulkhead 7 so that the lateral spacing of the hopper elements is automatically adjusted. The front elements of the hopper 32 and 32 are adjusted on rods or other supports 33, 33' on one side, and 33 33 on the other, each hopper front portion includes a lower portion 32a 32a, and upper element 34, 34' that is mounted on hinges so that they may be swung out of the way and additional blocks of material inserted horizontally into the hopper. The hinges may be spring biased to their block retaining postion.

Having thus described my invention, 1 claim:

1. A machine to cut cavities in blocks of heat severable material comprising a frame, means to convey successive blocks of material backward into the frame and forward therefrom, said means to carry said blocks carrying cam means having a front face and a rear face, rail means converging with the path of said blocks into said frame toward the back of said frame, an assembly consisting of carriage means and a changeable die secured to said carriage means mounted on said rail means, said die comprising heated wires extending toward the path of said blocks of material, said assembly being provided with first and second cam engaging means, said first cam engaging means being positioned to be engaged by said front face of said cam means as the block is moved toward the back of said frame by motion of said means to convey blocks whereby said assembly will be moved along said rails in a direction converging with the movement of said block so that the said wires of said die enter said block under the influence of said front cam face, said second cam engaging means being spaced from said first cam engaging means a distance to provide lost motion as the block is moved forward in the machine prior to the engagement of the backface of said cam means with said second cam engaging means to move said assembly away from said block and to determine the path of said die wire as it is withdrawn from said block.

2. The machine of claim 1 in which hopper means is provided to supply successive blocks of material to the machine.

3. The machine of claim 2 in which a movable shelf is positioned below said hopper means to receive each successive block, said means to convey said block being provided with means to position said shelf below said hopper means prior to delivery of a successive block of material to be cut.

4. The machine of claim 1 in which said frame has one stationary side carrying a horizontal drive shaft means on which part of said means to convey successive blocks is mounted, and carries one rail of the rail means, the other side of said frame being adjustably movable with respect to the stationary side of the frame and carrying mirror images of the elements on said stationary side of the frame, including a drive shaft carrying half of said means to convey successive blocks and mounted on said rail means to cut blocks of different widths.

5. The machine of claim 4 in which adjustable hopper means are mounted, one half on the fixed side of said a second rail means carrying carriage means whereby 5 frame, and the other half on the movable side.

assemblies of different widths may be selectively 

1. A machine to cut cavities in blocks of heat severable material comprising a frame, means to convey successive blocks of material backward into the frame and forward therefrom, said means to carry said blocks carrying cam means having a front face and a rear face, rail means converging with the path of said blocks into said frame toward the back of said frame, an assembly consisting of carriage means and a changeable die secured to said carriage means mounted on said rail means, said die comprising heated wires extending toward the path of said blocks of material, said assembly being provided with first and second cam engaging means, said first cam engaging means being positioned to be engaged by said front face of said cam means as the block is moved toward the back of said frame by motion of said means to convey blocks whereby said assembly will be moved along said rails in a direction converging with the movement of said block so that the said wires of said die enter said block under the influence of said front cam face, said second cam engaging means being spaced from said first cam engaging means a distance to provide lost motion as the block is moved forward in the machine prior to the engagement of the backface of said cam means with said second cam engaging means to move said assembly away from said block and to determine the path of said die wire as it is withdrawn from said block.
 2. The machine of claim 1 in which hopper means is provided to supply successive blocks of material to the machine.
 3. The machine of claim 2 in which a movable shelf is positioned below said hopper means to receive each successive block, said means to convey said block being provided with means to position said shelf below said hopper means prior to delivery of a successive block of material to be cut.
 4. The machine of claim 1 in which said frame has one stationary side carrying a horizontal drive shaft means on which part of said means to convey successive blocks is mounted, and carries one rail of the rail means, the other side of said frame being adjustably movable with respect to the stationary side of the frame and carrying mirror images of the elements on said stationary side of the frame, including a drive shaft carrying half of said means to convey successive blocks and a second rail means carrying carriage means whereby assemblies of different widths may be selectively mounted on said rail means to cut blocks of different widths.
 5. The machine of claim 4 in which adjustable hopper means are mounted, one half on the fixed side of said frame, and the other half on the movable side. 